inet/rcmd.c

   1 /*
   2  * Copyright (c) 1983, 1993, 1994
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #if defined(LIBC_SCCS) && !defined(lint)
  35 static char sccsid[] = "@(#)rcmd.c      8.3 (Berkeley) 3/26/94";
  36 #endif /* LIBC_SCCS and not lint */
  37
  38 #include <sys/param.h>
  39 #include <sys/socket.h>
  40 #include <sys/stat.h>
  41
  42 #include <netinet/in.h>
  43 #include <arpa/inet.h>
  44
  45 #include <signal.h>
  46 #include <fcntl.h>
  47 #include <netdb.h>
  48 #include <unistd.h>
  49 #include <pwd.h>
  50 #include <errno.h>
  51 #include <stdio.h>
  52 #include <ctype.h>
  53 #include <string.h>
  54
  55 #define MIN(A, B) ((A) < (B) ? (A) : (B))
  56
  57
  58 int     __ivaliduser __P((FILE *, u_int32_t, const char *, const char *));
  59 static int __icheckhost __P((u_int32_t, char *));
  60
  61 int
  62 rcmd(ahost, rport, locuser, remuser, cmd, fd2p)
  63         char **ahost;
  64         u_short rport;
  65         const char *locuser, *remuser, *cmd;
  66         int *fd2p;
  67 {
  68         struct hostent *hp;
  69         struct sockaddr_in sin, from;
  70         fd_set reads;
  71         int32_t oldmask;
  72         pid_t pid;
  73         int s, lport, timo;
  74         char c;
  75
  76         pid = getpid();
  77         hp = gethostbyname(*ahost);
  78         if (hp == NULL) {
  79                 herror(*ahost);
  80                 return (-1);
  81         }
  82         *ahost = hp->h_name;
  83         oldmask = sigblock(sigmask(SIGURG));
  84         for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
  85                 s = rresvport(&lport);
  86                 if (s < 0) {
  87                         if (errno == EAGAIN)
  88                                 (void)fprintf(stderr,
  89                                     _("rcmd: socket: All ports in use\n"));
  90                         else
  91                                 (void)fprintf(stderr, "rcmd: socket: %s\n",
  92                                     strerror(errno));
  93                         sigsetmask(oldmask);
  94                         return (-1);
  95                 }
  96                 fcntl(s, F_SETOWN, pid);
  97                 sin.sin_family = hp->h_addrtype;
  98                 bcopy(hp->h_addr_list[0], &sin.sin_addr,
  99                       MIN (sizeof (sin.sin_addr), hp->h_length));
 100                 sin.sin_port = rport;
 101                 if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
 102                         break;
 103                 (void)close(s);
 104                 if (errno == EADDRINUSE) {
 105                         lport--;
 106                         continue;
 107                 }
 108                 if (errno == ECONNREFUSED && timo <= 16) {
 109                         (void)sleep(timo);
 110                         timo *= 2;
 111                         continue;
 112                 }
 113                 if (hp->h_addr_list[1] != NULL) {
 114                         int oerrno = errno;
 115
 116                         (void)fprintf(stderr, _("connect to address %s: "),
 117                             inet_ntoa(sin.sin_addr));
 118                         __set_errno (oerrno);
 119                         perror(0);
 120                         hp->h_addr_list++;
 121                         bcopy(hp->h_addr_list[0], &sin.sin_addr,
 122                               MIN (sizeof (sin.sin_addr), hp->h_length));
 123                         (void)fprintf(stderr, _("Trying %s...\n"),
 124                             inet_ntoa(sin.sin_addr));
 125                         continue;
 126                 }
 127                 (void)fprintf(stderr, "%s: %s\n", hp->h_name, strerror(errno));
 128                 sigsetmask(oldmask);
 129                 return (-1);
 130         }
 131         lport--;
 132         if (fd2p == 0) {
 133                 write(s, "", 1);
 134                 lport = 0;
 135         } else {
 136                 char num[8];
 137                 int s2 = rresvport(&lport), s3;
 138                 int len = sizeof(from);
 139
 140                 if (s2 < 0)
 141                         goto bad;
 142                 listen(s2, 1);
 143                 (void)snprintf(num, sizeof(num), "%d", lport);
 144                 if (write(s, num, strlen(num)+1) != strlen(num)+1) {
 145                         (void)fprintf(stderr,
 146                             _("rcmd: write (setting up stderr): %s\n"),
 147                             strerror(errno));
 148                         (void)close(s2);
 149                         goto bad;
 150                 }
 151                 FD_ZERO(&reads);
 152                 FD_SET(s, &reads);
 153                 FD_SET(s2, &reads);
 154                 __set_errno (0);
 155                 if (select(1 + (s > s2 ? s : s2), &reads, 0, 0, 0) < 1 ||
 156                     !FD_ISSET(s2, &reads)) {
 157                         if (errno != 0)
 158                                 (void)fprintf(stderr,
 159                                    _("rcmd: select (setting up stderr): %s\n"),
 160                                    strerror(errno));
 161                         else
 162                                 (void)fprintf(stderr,
 163                              _("select: protocol failure in circuit setup\n"));
 164                         (void)close(s2);
 165                         goto bad;
 166                 }
 167                 s3 = accept(s2, (struct sockaddr *)&from, &len);
 168                 (void)close(s2);
 169                 if (s3 < 0) {
 170                         (void)fprintf(stderr,
 171                             "rcmd: accept: %s\n", strerror(errno));
 172                         lport = 0;
 173                         goto bad;
 174                 }
 175                 *fd2p = s3;
 176                 from.sin_port = ntohs((u_short)from.sin_port);
 177                 if (from.sin_family != AF_INET ||
 178                     from.sin_port >= IPPORT_RESERVED ||
 179                     from.sin_port < IPPORT_RESERVED / 2) {
 180                         (void)fprintf(stderr,
 181                             _("socket: protocol failure in circuit setup\n"));
 182                         goto bad2;
 183                 }
 184         }
 185         (void)write(s, locuser, strlen(locuser)+1);
 186         (void)write(s, remuser, strlen(remuser)+1);
 187         (void)write(s, cmd, strlen(cmd)+1);
 188         if (read(s, &c, 1) != 1) {
 189                 (void)fprintf(stderr,
 190                     "rcmd: %s: %s\n", *ahost, strerror(errno));
 191                 goto bad2;
 192         }
 193         if (c != 0) {
 194                 while (read(s, &c, 1) == 1) {
 195                         (void)write(STDERR_FILENO, &c, 1);
 196                         if (c == '\n')
 197                                 break;
 198                 }
 199                 goto bad2;
 200         }
 201         sigsetmask(oldmask);
 202         return (s);
 203 bad2:
 204         if (lport)
 205                 (void)close(*fd2p);
 206 bad:
 207         (void)close(s);
 208         sigsetmask(oldmask);
 209         return (-1);
 210 }
 211
 212 int
 213 rresvport(alport)
 214         int *alport;
 215 {
 216         struct sockaddr_in sin;
 217         int s;
 218
 219         sin.sin_family = AF_INET;
 220         sin.sin_addr.s_addr = INADDR_ANY;
 221         s = socket(AF_INET, SOCK_STREAM, 0);
 222         if (s < 0)
 223                 return (-1);
 224         for (;;) {
 225                 sin.sin_port = htons((u_short)*alport);
 226                 if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
 227                         return (s);
 228                 if (errno != EADDRINUSE) {
 229                         (void)close(s);
 230                         return (-1);
 231                 }
 232                 (*alport)--;
 233                 if (*alport == IPPORT_RESERVED/2) {
 234                         (void)close(s);
 235                         __set_errno (EAGAIN);           /* close */
 236                         return (-1);
 237                 }
 238         }
 239 }
 240
 241 int     __check_rhosts_file = 1;
 242 char    *__rcmd_errstr;
 243
 244 int
 245 ruserok(rhost, superuser, ruser, luser)
 246         const char *rhost, *ruser, *luser;
 247         int superuser;
 248 {
 249         struct hostent *hp;
 250         u_int32_t addr;
 251         char **ap;
 252
 253         if ((hp = gethostbyname(rhost)) == NULL)
 254                 return (-1);
 255         for (ap = hp->h_addr_list; *ap; ++ap) {
 256                 bcopy(*ap, &addr, sizeof(addr));
 257                 if (iruserok(addr, superuser, ruser, luser) == 0)
 258                         return (0);
 259         }
 260         return (-1);
 261 }
 262
 263 /*
 264  * New .rhosts strategy: We are passed an ip address. We spin through
 265  * hosts.equiv and .rhosts looking for a match. When the .rhosts only
 266  * has ip addresses, we don't have to trust a nameserver.  When it
 267  * contains hostnames, we spin through the list of addresses the nameserver
 268  * gives us and look for a match.
 269  *
 270  * Returns 0 if ok, -1 if not ok.
 271  */
 272 int
 273 iruserok(raddr, superuser, ruser, luser)
 274         u_int32_t raddr;
 275         int superuser;
 276         const char *ruser, *luser;
 277 {
 278         register char *cp;
 279         struct stat sbuf;
 280         struct passwd *pwd;
 281         FILE *hostf;
 282         uid_t uid;
 283         int first;
 284
 285         first = 1;
 286         hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
 287 again:
 288         if (hostf) {
 289                 if (__ivaliduser(hostf, raddr, luser, ruser) == 0) {
 290                         (void)fclose(hostf);
 291                         return (0);
 292                 }
 293                 (void)fclose(hostf);
 294         }
 295         if (first == 1 && (__check_rhosts_file || superuser)) {
 296                 char *pbuf;
 297                 size_t dirlen;
 298
 299                 first = 0;
 300                 if ((pwd = getpwnam(luser)) == NULL)
 301                         return (-1);
 302
 303                 dirlen = strlen (pwd->pw_dir);
 304                 pbuf = alloca (dirlen + sizeof "/.rhosts");
 305                 memcpy (pbuf, pwd->pw_dir, dirlen);
 306                 memcpy (pbuf + dirlen, "/.rhosts", sizeof "/.rhosts");
 307
 308                 /*
 309                  * Change effective uid while opening .rhosts.  If root and
 310                  * reading an NFS mounted file system, can't read files that
 311                  * are protected read/write owner only.
 312                  */
 313                 uid = geteuid();
 314                 (void)seteuid(pwd->pw_uid);
 315                 hostf = fopen(pbuf, "r");
 316                 (void)seteuid(uid);
 317
 318                 if (hostf == NULL)
 319                         return (-1);
 320                 /*
 321                  * If not a regular file, or is owned by someone other than
 322                  * user or root or if writeable by anyone but the owner, quit.
 323                  */
 324                 cp = NULL;
 325                 if (lstat(pbuf, &sbuf) < 0)
 326                         cp = _(".rhosts lstat failed");
 327                 else if (!S_ISREG(sbuf.st_mode))
 328                         cp = _(".rhosts not regular file");
 329                 else if (fstat(fileno(hostf), &sbuf) < 0)
 330                         cp = _(".rhosts fstat failed");
 331                 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
 332                         cp = _("bad .rhosts owner");
 333                 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
 334                         cp = _(".rhosts writeable by other than owner");
 335                 /* If there were any problems, quit. */
 336                 if (cp) {
 337                         __rcmd_errstr = cp;
 338                         (void)fclose(hostf);
 339                         return (-1);
 340                 }
 341                 goto again;
 342         }
 343         return (-1);
 344 }
 345
 346 /*
 347  * XXX
 348  * Don't make static, used by lpd(8).
 349  *
 350  * Returns 0 if ok, -1 if not ok.
 351  */
 352 int
 353 __ivaliduser(hostf, raddr, luser, ruser)
 354         FILE *hostf;
 355         u_int32_t raddr;
 356         const char *luser, *ruser;
 357 {
 358         register char *user, *p;
 359         int ch;
 360         char *buf = NULL;
 361         size_t bufsize = 0;
 362         ssize_t nread;
 363
 364         while ((nread = getline (&buf, &bufsize, hostf)) > 0) {
 365                 buf[bufsize - 1] = '\0'; /* Make sure it's terminated.  */
 366                 p = buf;
 367                 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
 368                         *p = isupper(*p) ? tolower(*p) : *p;
 369                         p++;
 370                 }
 371                 if (*p == ' ' || *p == '\t') {
 372                         *p++ = '\0';
 373                         while (*p == ' ' || *p == '\t')
 374                                 p++;
 375                         user = p;
 376                         while (*p != '\n' && *p != ' ' &&
 377                             *p != '\t' && *p != '\0')
 378                                 p++;
 379                 } else
 380                         user = p;
 381                 *p = '\0';
 382                 if (__icheckhost(raddr, buf) &&
 383                     strcmp(ruser, *user ? user : luser) == 0) {
 384                         free (buf);
 385                         return (0);
 386                 }
 387         }
 388         free (buf);
 389         return (-1);
 390 }
 391
 392 /*
 393  * Returns "true" if match, 0 if no match.
 394  */
 395 static int
 396 __icheckhost(raddr, lhost)
 397         u_int32_t raddr;
 398         register char *lhost;
 399 {
 400         register struct hostent *hp;
 401         register u_int32_t laddr;
 402         register char **pp;
 403
 404         /* Try for raw ip address first. */
 405         if (isdigit(*lhost) && (int32_t)(laddr = inet_addr(lhost)) != -1)
 406                 return (raddr == laddr);
 407
 408         /* Better be a hostname. */
 409         if ((hp = gethostbyname(lhost)) == NULL)
 410                 return (0);
 411
 412         /* Spin through ip addresses. */
 413         for (pp = hp->h_addr_list; *pp; ++pp)
 414                 if (!bcmp(&raddr, *pp, sizeof(u_int32_t)))
 415                         return (1);
 416
 417         /* No match. */
 418         return (0);
 419 }